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Climatic Drivers in Central Victoria

Climatic Drivers in Central Victoria. Dale Grey DPI Cobram Big Hill Cropping Agronomist Friday, 24 th June 2011. Classic Mediterranean Rainfall pattern. Annual Rainfall Absurd level of variability.

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Climatic Drivers in Central Victoria

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  1. Climatic Drivers in Central Victoria Dale Grey DPI Cobram Big Hill Cropping Agronomist Friday, 24th June 2011

  2. Classic Mediterranean Rainfall pattern

  3. Annual Rainfall Absurd level of variability

  4. Federation WWII Annual- 5 year moving average

  5. Summer Autumn Spring Winter

  6. Autumn rainfall 5 year moving average Macedon Harrietville Lake Wartook Warburton Ballarat Woods Point

  7. November 2006 El Niño Cold off Darwin-Qld El Niño surface temperature anomaly

  8. December 31st 2007 La Niña Warm off Darwin-Qld Classic horseshoe shape of warm water for La Niña

  9. August 2006 Cool Broome-Brisbane x x IOD+ Strong in 2006, weak IOD+ in 2007 and strong again in 2008, the triple whammy.

  10. October 21st 2010 x Warm Broome-Brisbane x IOD- Only a weak one this year. Started in late Sept, through October, gone in November. Probably wont be recognised as an official IOD- year

  11. El niño 23 years 24 years 1877-2010 18 years La niña 29 years

  12. The SAM index is calculated by the differences in pressure between 40o and 65o degrees latitude Most of the upward trend is over Summer and Autumn Southern Annular Mode, SAM or AAO Measures the strength of polar westerlies in the Southern Ocean.

  13. Source = NOAA 2010 the winter SAM was strongly Positive. Developing La Nina trumped this in Victoria and we got average rainfall, speak to someone in WA and Sth Africa about it though.

  14. Source = NOAA 2009 the winter SAM was strongly Negative. The developing uncoupled El Nino failed to trump this in Victoria.

  15. 11 years +SAM 1957-2009 13 years -SAM

  16. Sub-tropical ridge The Sub tropical ridges originate as a result of the Hadley Cells emanating from the Equator. One in each hemisphere, dry, descending air, causing high pressure. Mediterranean climates and deserts occur in these regions of the world.

  17. July 2009 Winter pattern, strong highs centered over the top of the Bight Jan 2009 Sub Tropical Ridge The High pressure belt lying over Australia and at all mid latitudes of the world. Summer pattern, centre of highs over Melbourne

  18. 30 years 27 years 1890-2009 28 years 27 years

  19. Maroon Sweet Pea, October 2011, Koonoomoo, taken by D Grey

  20. Winter Pacific Ocean- Mixed Indian Ocean- Neutral (weak IOD+) Winter Rainfall- Average Winter Temperature- Average/slightly warmer

  21. Spring Pacific Ocean- Mixed Indian Ocean- Neutral (weak IOD+) Spring Rainfall- Mixed Spring Temperature- Average

  22. That’s all Folks Nias Island, west Sumatra Diani Beach, southern Kenya See me to Subscribe to “The Break” eNEWSLETTER

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